The lifetime of traditional light sources (incandescent, fluorescent, and high-intensity discharge lamps) is estimated through industry-standard lamp rating procedures. The number is determined by an operation that runs a large, statistically significant sample of lamps until 50% have failed and that number of hours defines “rated life” for that lamp. Based on years of experience with traditional light sources, lighting experts can confidently use lamp life ratings, along with known lumen depreciation curves, to design the lighting for a space, and to determine equipment change schedules and economic payback. This aspect of predictive life or half-life of a light source is not true with Light Emitting Diodes (LED).
One reason why LED-based luminaires have gained popularity is because of their operational longevity and low power consumption. LEDs generally do not fail abruptly like traditional light sources; instead, their light output slowly diminishes over time. However, LED light sources can have such long lives that life testing and acquiring real application data on long-term reliability becomes problematic—for example, new versions of products are available before current ones can be fully tested. On top of that, LED light output and useful life are highly dependent on electrical and thermal conditions associated with the luminaire, associated systems, and the environment in which the luminaire is installed.
Digital intelligent lighting control systems can switch and dim individual luminaries in a light scene or space, such as an area within a building, which provides a great amount of flexibility, for example, setting appropriate LED output under particular conditions including the current LED lumen depreciation, to maintain desired levels of LED output. Such lighting control systems have user-friendly features for installation, programming, and operation. For example, lighting control systems can be integrated into a building management system as a subsystem of the central lighting controls.
A lighting control network generally includes one or more lighting devices; e.g., an electrical ballast including a luminaire, a light source such as an LED, and a dimmer, among other things. The dimmer must support specific interfaces for receiving control inputs for the luminaire/light source and dimming the light appropriately. Different lighting devices can support different control interfaces for dimming, e.g., to generate a particular color temperature as between different LED brands and/or powers.
The color temperature of a luminaire is the look and feel of the light produced by the luminaire. Color temperature is measured in degrees Kelvin (K) on a scale of 1000-10,000. Color temperature indicates, among other things, the color characteristic of lights coming out of luminaires located in an environment. In a typical commercial and/or residential environment, the luminaires' color temperatures fall between 2000K and 6500K. At the lower end of the scale, from 2000K to 3000K, the light produced is called “warm white” and ranges from orange to yellow-white in appearance. At the middle portion of the scale, from 3100K to 4500K, the light produced is called “cool white” or “bright white.” Luminaires within this range emit a more neutral white light and may even have a slightly blue tint. Light produced above 4500K brings us to “daylight” color temperature of light. Luminaires with color temperatures of 4500K and above will give off a blue-white light that mimics daylight. The color temperature of the luminaire corresponds to the lumen level of the luminaire.
Current lighting control systems do not provide a system or method for allowing users to predict, after the fixture has been installed, when lumen degradation has occurred to the point where the light needs to be replaced.
For example, current lighting control systems include a Digital Addressable Lighting Interface (DALI®) protocol based system which includes a controller, a driver, and a signal converter. The DALI® system is capable of regulating color temperature of a luminaire by adjusting a dimming level of the luminaire so long as the luminaire is the same make and type throughout the entire system, which has been pre-designed around such luminaires.
At least one drawback of the DALI® system and other current systems is that current systems may use a single or a fixed dimming control technology which may not be adjusted during the life or state of degradation of a luminaire. Furthermore, these systems cannot control dynamic environments in which luminaires not present at the time of inception are introduced; that is, these systems must be developed and tested with the technology and parameters available during initial commissioning of the lighting system. There is no system learning capacity to dynamically integrate new luminaires and different types of LEDs, for example, with different powers, into the system.
Further, current techniques for controlling a dimming level of luminaires in a networked lighting system may require multiple standard protocols to accommodate different types of luminaires. The implementations of the techniques are accordingly varied and the resultant dimming levels of luminaires cannot be correlated across groups. For example, the color temperature of each luminaire may be individually controlled, e.g., every luminaire may have a sensor and a dimming control that can be set to a specific color temperature, but when a group of different types of luminaires occupy the same space, such as a single room, controlling the overall dimming level to produce a correct overall color temperature in the room is difficult. This problem is exacerbated as individual LEDs of particular luminaires respectively degrade at varying rates over time.
Thus, devices, systems, and/or methods for allowing a user who installs tens of thousands of luminaire systems to predict when and how much every luminaire has been degraded and/or adjust dimming level control over time provides enhanced convenience, control, and economics in lighting systems. The devices, systems, and methods may scale to very large numbers of luminaires at a global level. Such devices, systems, and methods may, for example, identify in real time the current state, such as ON/OFF, color temperature, and/or degradation state of at least one luminaire. For purposes of this disclosure, “real time” means substantial concurrency. “Real time” does not include any particular timeframe or limitation.
Such devices, systems, and methods may also be capable of maintaining the color temperature levels of each luminaire regardless of dimming protocols, type of luminaire, or environmental characteristics associated with the luminaire. Devices, systems, and methods which allow any dimming protocol to be used in the same space and yet generate a specific color temperature for the space provide further flexibility in lighting control systems.
For purposes of this disclosure, “protocol” means, for example and without limitation, one or more instructions, sequences, processes, algorithms, responses, or actions.
For purposes of this disclosure, “real time” means substantial concurrency and does not include any particular time frame or limitation.
For purposes of this disclosure, a “driver” is, for example and without limitation, a separate or integral device, system, mechanism, etc. for actuating, initiating, controlling, or communicating a command or operation as part of the exemplary disclosed devices, systems, and methods.
In view of the above, the disclosed devices, systems, and methods use lumen degradation, predictive life, dimming control and protocols, and environmental conditions of a luminaire, among other things, to dynamically generate, change, and/or maintain desired color temperatures for a luminaire, group of luminaires, or lighted space.